Robin van Persie has warned Manchester United's rivals that they will not be weakened next season because David Moyes has replaced Sir Alex Ferguson, with the Dutchman clear that the champions want to achieve more than only defend the title.

Van Persie has completed his first week under Moyes after joining United's pre-season tour in Sydney. After scoring in the 5-1 win over the A-League All Stars on Saturday, he accepted that other teams will look at the retirement of Ferguson, domestic football's most successful manager, and believe United will be vulnerable.

The striker said: "They can think what they want to think. It doesn't matter to us. What matters to us is the way that we work. Trust me, we will work very hard. It's a huge challenge to all of us and it is one we are looking forward to. I hope it will be the same this time [as last season] as I want to win more this time. The club wants to win more. Last year we won the league and that was great but this time we want to win the league and more as well."

The 29-year-old was vital to United regaining the championship and underlined his hunger to keep on improving. "I don't let things get in the way," he said. "I want chances every day, every session, every game. I just see big opportunities. I still have more years left and it's not like I am saying: 'Yeah, we won the league so that's me done'. I want more now. It makes me even more hungry. I was very hungry last year but now I am more hungry. We have a great bunch of players so we can win more and do better. I always try to do better than the day before so, yes, I can do better than last year."

With José Mourinho back as Chelsea's coach and Manchester City replacing Roberto Mancini with Manuel Pellegrini, Van Persie understands that United will have to raise their levels of performance. "We have to improve to stay ahead of them because over the last few years the English league has become better and better," he said. "Every single team has got harder to beat. Everyone wants to be successful. Moyes wants to be successful. He has been working very hard and he has spoken to every single player individually.

"It's different [without Ferguson]. Of course it was a great year last time. It was my first year with him and the first year at the club I had with him. It was a great year for the club and we all did great things together," he said. "But now it's a new year and I am very much looking forward to it with a new manager and staff. For now we have the same players. He [Moyes] is very nice. He works very well. It's only based on a few sessions but I loved them."

Phil Jones, who played in central defence against the All Stars, is not concerned what position he plays under Moyes. "We haven't spoken about it yet, but I'm sure as the tour progresses then it will arise," he said. "It's like I said last season when I was playing right-back, centre-back and centre-midfield, I just enjoy playing football and if that means playing in different positions then that's fine, I just want to play. Hopefully I can play plenty of games."

Danny Welbeck and Jesse Lingard, with two goals each, were United's other scorers, while Besart Berisha grabbed a consolation for the All Stars.